Trying to Create and Use a Mailing List

We are trying to create and use a mailing list to send out notifications to members of our website. We host most of their E-mails on our server, but there is no forum or database as per say where they are registering as members.
But none the less I tried to use the mailing list under the cPanel reseller account to create a list, but I can't get it to mail out any emails. I was testing it with just 5 users.

the mailing list name is sur1 the page said mail to sur1@surveyors.org to send message to all subscribers. This did not work. Obviously I am doing something wrong. Does anyone have any idea what that could be. If i need to provide more information just let me know what I need to present.

Also would there be a better way that to use that mailing list function? we will have roughly 40,000 members on the list when it is finished. After I have it tested and working.

Thanks for any help,

:: EDIT ::
also i noticed when looking through the configuration that it seemed like just anyone could email that list and it would go out. IS this correct? If so can i make it so only one address can mail to that list?

This can most likely be achieved, I think it would be best however if you submit a ticket via the link at the bottom of this post. This will give us a chance to take a closer look at this issue and get you going as soon as we can.